Thermodynamics is the fundamental branch of physics that governs the principles of heat transfer between a system and its surroundings. This paper explores system, surroundings andboundary & the mechanisms of heat flow, including conduction, convection, and radiation, in various thermodynamic systems. Also describes the types of boundaries, characteristics and functions of boundary. It examines the laws of thermodynamics, emphasizing the role of entropy and energy conservation in heat exchange processes. The study also delves into realworld applications, such as heat engines, refrigeration cycles, and thermal insulation technologies, highlighting their efficiency and limitations. By analysing theoretical models and experimental findings, this research provides a deeper understanding of heat transfer phenomena and their implications for energy management and sustainability. The findings contribute to optimizing thermal systems for industrial, environmental, and engineering applications.

Thermodynamics, Heat Engines, Heat Energy